Fluid Dynamics...

[Blondie]

If I was to use experimentally based tables, such as those available from ammunition manufacturers, I would have to ask for the specific ammunition make, caliber, and type wouldn't I?

You assume too much me thinks.

Oh no, I know exactly how hard combustion is to model, and exactly how unlikely it is that you have a computer simulation of the various variables set to run at a moment's notice.

Your tables are experimentally derived.

Alright, I'll grant you I use experimentally derived tables for the charge types, however the rest is calculated using the proper formulae.

Here's a quiz: Give me the velocity and kinetic energy of a cartridge firing a 400 grain boat tail projectile with an 85 grain powder charge down a 22" barrel at both the muzzle and at 400 yards assuming 0 wind speed. For an obvious genius like you, this ought to be easy. Extra points for calculating the trajectory and drop.

[GreyICE]

Alright, I'll grant you I use experimentally derived tables for the charge types, however the rest is calculated using the proper formulae.

Here's a quiz: Give me the velocity and kinetic energy of a cartridge firing a 400 grain boat tail projectile with an 85 grain powder charge down a 22" barrel at both the muzzle and at 400 yards assuming 0 wind speed. For an obvious genius like you, this ought to be easy. Extra points for calculating the trajectory and drop.

How would having a chart handy make me a genius? It would make me able to read a chart.

Now if I could model combustion accurately, yeah, that probably would make me a genius. And we might have a pulse detonation engine.

[lpetrich]

Here's a Wikipedia article on the physics of guns: Physics of firearms

News Release - Magnetic field accelerates pellets -- a magnetic-induction gun that shoots its bullets up to 20 km/s.

Explosive-powered guns are limited by the speed of sound in the exploded material, which is roughly sqrt(energy released per unit mass). This can be well above the speed of sound in the surrounding air, however.

[mistermack]

Explosive-powered guns are limited by the speed of sound in the exploded material,

That's what the question is about. Is there a link showing why that is so?

[lpetrich]

That physics-of-firearms page may have some explanation of that, but here's a very simple, short, handwaving answer:

Kinetic energy = (1/2)*(mass)*(velocity)2

This means that sound velocity ~ sqrt(energy per unit mass)

Part of the explosive's energy goes into the bullet and part of it into expanding the explosive itself. So

Energy released ~ (1/2)*((mass of explosive) + (mass of bullet))*(typical velocities)2

Thus, (bullet velocity) ~ sqrt((explosive energy)/((bullet mass)+(explosive mass))) < sqrt((explosive energy)/(explosive mass)) ~ (sound velocity of exploded material)

Or, (bullet velocity) <~ (sound velocity of exploded material)

[JacksSmirkingRevenge]

[Tigger]

[mistermack]

That physics-of-firearms page may have some explanation of that, but here's a very simple, short, handwaving answer:

Kinetic energy = (1/2)*(mass)*(velocity)2

This means that sound velocity ~ sqrt(energy per unit mass)

Part of the explosive's energy goes into the bullet and part of it into expanding the explosive itself. So

Energy released ~ (1/2)*((mass of explosive) + (mass of bullet))*(typical velocities)2

Thus, (bullet velocity) ~ sqrt((explosive energy)/((bullet mass)+(explosive mass))) < sqrt((explosive energy)/(explosive mass)) ~ (sound velocity of exploded material)

Or, (bullet velocity) <~ (sound velocity of exploded material)

Ok, sorry I asked.
.

[JacksSmirkingRevenge]

That physics-of-firearms page may have some explanation of that, but here's a very simple, short, handwaving answer:

Kinetic energy = (1/2)*(mass)*(velocity)2

This means that sound velocity ~ sqrt(energy per unit mass)

Part of the explosive's energy goes into the bullet and part of it into expanding the explosive itself. So

Energy released ~ (1/2)*((mass of explosive) + (mass of bullet))*(typical velocities)2

Thus, (bullet velocity) ~ sqrt((explosive energy)/((bullet mass)+(explosive mass))) < sqrt((explosive energy)/(explosive mass)) ~ (sound velocity of exploded material)

Or, (bullet velocity) <~ (sound velocity of exploded material)

Ok, sorry I asked.
.

Lol. Join the club.
I haven't had the heart to tell them I don't understand a fucking word they're talking about. I don't think I've been near an equation in well over 20 years - and I didn't understand them then.

[normal]

[JacksSmirkingRevenge]

Looking back at this thread made me lol. (Literally.)
One has to admire the way Ratz can take a fairly simple question and turn it into a forest of incomprehensible equations, pointless arguments and completely unrelated and irrelevent bollox.
Fucking awesome!

In fact, it's doubly awesome 'cos Tigger is in it.

[FBM]

And yeah. Tigg.

[Jason]

If I was to use experimentally based tables, such as those available from ammunition manufacturers, I would have to ask for the specific ammunition make, caliber, and type wouldn't I?

You assume too much me thinks.

Oh no, I know exactly how hard combustion is to model, and exactly how unlikely it is that you have a computer simulation of the various variables set to run at a moment's notice.

Your tables are experimentally derived.

Alright, I'll grant you I use experimentally derived tables for the charge types, however the rest is calculated using the proper formulae.

Here's a quiz: Give me the velocity and kinetic energy of a cartridge firing a 400 grain boat tail projectile with an 85 grain powder charge down a 22" barrel at both the muzzle and at 400 yards assuming 0 wind speed. For an obvious genius like you, this ought to be easy. Extra points for calculating the trajectory and drop.

What a cunt.

[Jason]

Miss ya Bro.


..Sorry for being such a Cunt.